package org.apache.lucene.search.highlight;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import org.apache.lucene.analysis.Token;

/**
 * One, or several overlapping tokens, along with the score(s) and the scope of
 * the original text
 * 
 * @author MAHarwood
 */
public class TokenGroup {

	private static final int MAX_NUM_TOKENS_PER_GROUP = 50;
	Token[] tokens = new Token[MAX_NUM_TOKENS_PER_GROUP];
	float[] scores = new float[MAX_NUM_TOKENS_PER_GROUP];
	int numTokens = 0;
	int startOffset = 0;
	int endOffset = 0;
	float tot;

	int matchStartOffset, matchEndOffset;

	void addToken(Token token, float score) {
		if (numTokens < MAX_NUM_TOKENS_PER_GROUP) {
			if (numTokens == 0) {
				startOffset = matchStartOffset = token.startOffset();
				endOffset = matchEndOffset = token.endOffset();
				tot += score;
			} else {
				startOffset = Math.min(startOffset, token.startOffset());
				endOffset = Math.max(endOffset, token.endOffset());
				if (score > 0) {
					if (tot == 0) {
						matchStartOffset = token.startOffset();
						matchEndOffset = token.endOffset();
					} else {
						matchStartOffset = Math.min(matchStartOffset, token
								.startOffset());
						matchEndOffset = Math.max(matchEndOffset, token
								.endOffset());
					}
					tot += score;
				}
			}
			tokens[numTokens] = token;
			scores[numTokens] = score;
			numTokens++;
		}
	}

	boolean isDistinct(Token token) {
		return token.startOffset() >= endOffset;
	}

	void clear() {
		numTokens = 0;
		tot = 0;
	}

	/**
	 * 
	 * @param index
	 *            a value between 0 and numTokens -1
	 * @return the "n"th token
	 */
	public Token getToken(int index) {
		return tokens[index];
	}

	/**
	 * 
	 * @param index
	 *            a value between 0 and numTokens -1
	 * @return the "n"th score
	 */
	public float getScore(int index) {
		return scores[index];
	}

	/**
	 * @return the end position in the original text
	 */
	public int getEndOffset() {
		return endOffset;
	}

	/**
	 * @return the number of tokens in this group
	 */
	public int getNumTokens() {
		return numTokens;
	}

	/**
	 * @return the start position in the original text
	 */
	public int getStartOffset() {
		return startOffset;
	}

	/**
	 * @return all tokens' scores summed up
	 */
	public float getTotalScore() {
		return tot;
	}
}
